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状态机

状态机是一种用来进行对象行为建模的工具，其作用主要是描述对象在它的生命周期内所经历的状态序列，以及如何响应来自外界的各种事件。摘录自这个大神的文章状态机引擎选型

需注意的是状态机并不是流程引擎,没有流程图及其它元素，仅包含状态，事件等相关内容。

示例说明

网上能找到的示例大多都过于复杂，所以写了一个简单的示例下面的代码定义了一个极简的状态机,仅包含两个状态(上班,下班),一个事件(通勤),通过web页面操作添加状态机及状态转换,集成了spring-statemachine-data-jpa进行持久化.

SpringBoot2.x配置说明

Pom.xml

        <dependency>
            <groupId>org.springframework.statemachine</groupId>
            <artifactId>spring-statemachine-starter</artifactId>
            <version>2.2.0.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.statemachine</groupId>
            <artifactId>spring-statemachine-data-jpa</artifactId>
            <version>2.2.0.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>

JAVA配置

持久化配置

@Configuration
public class StateMachineJpaConfig {

    /**
     * StateMachineRuntimePersister为状态机运行时持久化配置
     * @param jpaStateMachineRepository
     * @return
     */
    @Bean
    public StateMachineRuntimePersister<String, String, String> stateMachineRuntimePersister(
            JpaStateMachineRepository jpaStateMachineRepository) {
        return new JpaPersistingStateMachineInterceptor<>(jpaStateMachineRepository);
    }

    /**
     * StateMachineService为状态状态机持久化控制,用于获取或关闭状态机
     * @param stateMachineFactory
     * @param stateMachineRuntimePersister
     * @return
     */
    @Bean
    public StateMachineService<String, String> stateMachineService(
            StateMachineFactory<String, String> stateMachineFactory,
            StateMachineRuntimePersister<String, String, String> stateMachineRuntimePersister) {
        return new DefaultStateMachineService<String, String>(stateMachineFactory, stateMachineRuntimePersister);
    }
}

JpaStateMachineRepository:具体数据层操作
StateMachineService: 服务层操作，业务使用时注入即可

状态机配置

@EnableStateMachine为单例模式通常用于维护一个状态，并不适合此示例所以使用@EnableStateMachineFactory

@Configuration
@EnableStateMachineFactory
public class StateMachineConfig extends StateMachineConfigurerAdapter<String, String> {


    @Autowired
    private StateMachineRuntimePersister<String, String, String> stateMachineRuntimePersister;

    @Autowired
    private StateMachineLogListener logListener;

    @Override
    public void configure(StateMachineConfigurationConfigurer<String, String> config)
            throws Exception {
        config
                .withPersistence()
                .runtimePersister(stateMachineRuntimePersister)
                .and()
                .withConfiguration().listener(logListener);
    }

    @Override
    public void configure(StateMachineStateConfigurer<String, String> states)
            throws Exception {
        states
                .withStates()
                .initial("宿舍")
                .state("公司");
    }

    @Override
    public void configure(StateMachineTransitionConfigurer<String, String> transitions)
            throws Exception {
        transitions
                .withExternal()
                .source("宿舍").target("公司")
                .event("通勤")
                .and()
                .withExternal()
                .source("公司").target("宿舍")
                .event("通勤");
    }
}

StateMachineStateConfigurer：状态配置，可有多个状态，初始为initial，结束为end，示例为了方便只配置了初始状态，其它配置请查阅文档。
StateMachineTransitionConfigurer：事件与状态关联配置。

监听配置

继承StateMachineListenerAdapter重写需监听的方法即可,通过方法名可推测监听的事件，就不详细介绍了。

@Slf4j
@Component
public class StateMachineLogListener extends StateMachineListenerAdapter<String, String> {

   private  StateContext stateContext;

   @Override
   public void stateChanged(State<String, String> from, State<String, String> to) {
      if(stateContext!=null){
         log.info("{} in stateChanged Listener",stateContext.getStateMachine().getId());
      }else{
         log.info("---------------------stateChanged---------------------------------------");
      }
   }

   @Override
   public void stateEntered(State<String, String> state) {
      if(stateContext!=null){
         log.info("{} in stateEntered Listener",stateContext.getStateMachine().getId());
      }else{
         log.info("---------------------stateEntered---------------------------------------");
      }
   }

   @Override
   public void stateExited(State<String, String> state) {
      if(stateContext!=null){
         log.info("{} in stateExited Listener",stateContext.getStateMachine().getId());
      }else{
         log.info("---------------------stateExited---------------------------------------");
      }
   }

   @Override
   public void eventNotAccepted(Message<String> event) {
      if(stateContext!=null){
         log.info("{} in eventNotAccepted Listener",stateContext.getStateMachine().getId());
      }else{
         log.info("---------------------eventNotAccepted---------------------------------------");
      }
   }

   @Override
   public void transition(Transition<String, String> transition) {
      if(stateContext!=null){
         log.info("{} in transition Listener",stateContext.getStateMachine().getId());
      }else{
         log.info("---------------------transition---------------------------------------");
      }
   }

   @Override
   public void transitionStarted(Transition<String, String> transition) {
      if(stateContext!=null){
         log.info("{} in transitionStarted Listener",stateContext.getStateMachine().getId());
      }else{
         log.info("---------------------transitionStarted---------------------------------------");
      }
   }

   @Override
   public void transitionEnded(Transition<String, String> transition) {
      if(stateContext!=null){
         log.info("{} in transitionEnded Listener",stateContext.getStateMachine().getId());
      }else{
         log.info("---------------------transitionEnded---------------------------------------");
      }
   }

   @Override
   public void stateMachineStarted(StateMachine<String, String> stateMachine) {
      if(stateContext!=null){
         log.info("{} in stateMachineStarted Listener",stateContext.getStateMachine().getId());
      }else{
         log.info("---------------------stateMachineStarted---------------------------------------");
      }
   }

   @Override
   public void stateMachineStopped(StateMachine<String, String> stateMachine) {
      if(stateContext!=null){
         log.info("{} in stateMachineStopped Listener",stateContext.getStateMachine().getId());
      }else{
         log.info("---------------------stateMachineStopped---------------------------------------");
      }
   }

   @Override
   public void stateMachineError(StateMachine<String, String> stateMachine, Exception exception) {
      if(stateContext!=null){
         log.info("{} in stateMachineError Listener",stateContext.getStateMachine().getId());
      }else{
         log.info("---------------------stateMachineError---------------------------------------");
      }
   }

   @Override
   public void extendedStateChanged(Object key, Object value) {
      if(stateContext!=null){
         log.info("{} in extendedStateChanged Listener",stateContext.getStateMachine().getId());
      }else{
         log.info("---------------------extendedStateChanged---------------------------------------");
      }
   }

   @Override
   public void stateContext(StateContext<String, String> stateContext) {
      if(stateContext!=null){
         this.stateContext = stateContext;
         log.info("{} in stateContext Listener",stateContext.getStateMachine().getId());
      }else{
         log.info("---------------------stateContext---------------------------------------");
      }
   }

}

完整代码

gitee.com/MeiJM/sprin…

参考资料

docs.spring.io/spring-stat…

segmentfault.com/a/119000000…

Spring boot 2.x 整合Spring-Statemachine

状态机